Isolator for passing an optical cable held on a phase line of a high tension aerial line

ABSTRACT

The insulator is constructed in two parts and can, therefore, also be fastened to an already-laid ADL cable. The two glued insulator halves, which are reinforced by sleeves that are pushed on at the end, are each made of a half-pipe having transverse and longitudinal stability, as well as an insulator element that partially surrounds the half-pipe. A casting resin brought into the cylindrical hollow space of the insulator connects the half-pipes sealed at the end with silicone stoppers, the GFK rod, and the cable to form a stable unit.

BACKGROUND OF THE INVENTION

In order to prevent danger to assembly and/or maintenance personnel, theoptical communication cable held on the phase cable of a high-voltageaerial line by an adhesive strip must be led in a voltage-free fashion,i.e., at ground potential, to the cable fitting fastened to the tower.The decoupling from the high-voltage of the phase cable is standardlyaccomplished by an insulator positioned before the cable fitting,through which the ADL (All Dielectric Lash) cable, as it is called, isrouted. Corresponding insulators are known from EP 0 303 740 A1 and fromDE 196 48 755 A1. However, these insulators cannot be retrofitted ontoalready-laid ADL cables.

In DE 32 42 008 A1, a suspension device is specified that is used forthe guiding of, in particular, light waveguide cables. This devicecomprises a guide part for guiding the light waveguide cable, which partis fastened to a tower for the high-voltage line. At both sides of theguide part, the suspension device is provided with a respectiveinsulating element. The respective insulating element can be made up ofa multiplicity of individual elements that can be put together.

SUMMARY OF THE INVENTION

The subject matter of the invention is an insulator with which, inparticular, an already-laid ADL cable can be guided and can be decoupledfrom the high voltage of the phase cable, and/or with which adisconnecting switch can easily be jumped or bypassed. This object isachieved according to the invention by an insulator comprising twoparts, which can be assembled around the cable, each part has ahalf-pipe and an insulator element that is connected to the half-pipe.

The proposed insulator contains two half-pipes or half-shells havingsufficient transverse and longitudinal stability, and preferably made ofglass-fiber-reinforced plastic (GFK), as well as an insulator elementthat surrounds the half-pipes at least partially and is made ofsilicone. In order to enable the individual components to be joined andheld in this position more easily, the half-pipes and the insulatorelement are respectively equipped with guide pins or, respectively,guide openings or bored guide holes, situated opposite each other.

In one of the half-pipes, a GFK rod protruding from the half-pipe can beglued in, whereby the GFK rod and the ADL cable to be guided throughpreferably have the same diameter.

At least one of the half-pipes comprises, outside the region covered bythe insulator element, bored filling holes and bored ventilation holes,in order to enable the hollow space formed by the joined halves to befilled with a high-voltage-stable or electrically insulating material,preferably an epoxy resin (e.g., Protolin), or, respectively, to allowthe air displaced by the filling compound to escape.

After the two insulator halves have been joined, a slit or slottedsleeve, preferably made of GFK, is pushed onto each of the twocylindrical insulator ends and is glued to the half-pipes.

In the assembly of the insulator, a twin-chamber sack containing asufficient quantity of a two-component silicone resin (preferablyLSR—Liquid Silicone Rubber) is preferably used. After the two componentshave been mixed, the silicone resin is applied to the edge surfaces ofthe silicone insulator halves, and the insulator halves are placedtogether and are heated to approximately 100° C. for approximately fiveminutes, and are thereby adhesively bonded to each other. Subsequently,the epoxy casting resin, which is used as a filling compound, preferablyProtolin 51, is brought, via the bored filling holes, into the hollowbody, which is sealed at its end side by means of two silicone stoppers.This resin fuses with the ADL cable(s) fixed in the respective half-pipeby a plastic compound (e.g., Prestik), with the GFK rod glued into oneof the half-pipes, and with the insulator halves, to form a unit havingtensile strength.

The insulator without GFK rod, placed on supports or hanging on the lineor phase cable, can jumper the tower or a disconnected switch.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing one half of the insulator;

FIG. 2 is a perspective view of two halves of the insulator, not yetfilled and sealed at the end,

FIG. 3 is a perspective view of an insulator half provided with a GFKrod and a GFK sleeve to be applied at the end;

FIG. 4 is a perspective view according to FIG. 3, including thecommunication cable fixed in the insulator half; and

FIG. 5 is a perspective view of the assembled insulator being filledwith a casting resin.

DESCRIPTION OF A PREFERRED EMBODIMENT

The lower insulator half, shown in FIG. 1, comprises a semi-cylindricalhalf-pipe or half-shell 2 and an insulator element 4 that comprises alikewise semi-cylindrical part that abuts immediately on the half-pipe2, as well as two silicone shields or fins 6 that extend at a rightangle to the semi-cylindrical part and that are formed in the shape ofsemicircular disks. While the insulator element 4 is preferablymanufactured from LSR (Liquid Silicone Rubber) or another siliconematerial, the half-pipe 2, which has transverse and longitudinalstability, is made of an epoxy or polyester resin. The bored holes 8present in the silicone shields 6 of the insulator element 4 are usedfor the reception and guiding of the connection pins 28 that are presentat corresponding points of the insulator element 22 with fins or shields26 of the second insulator half (see the right part of FIG. 2). Thehalf-pipe 2 is also equipped with hollow cylindrical openings or sleeves10 a for the guiding of the pins 10 b present in the second half-pipe20. In addition, the half-pipe 2 contains a bored hole 12 that is usedfor the filling of the assembled insulator. In FIG. 1, an epoxy rod 14is glued into the half-pipe 2, and the ADL cable that is to be guidedthrough and maintained at ground potential is designated 16. Theconstruction of the cable 16 inside the insulator is described in detailin DE 196 48 755 A1, and requires no further explanation here. Twosilicone stoppers 18 that are respectively cut open, i.e., that can bedivided, seal the insulator at its end side.

FIG. 2 shows the two insulator halves, each in a perspective view,before the joining, whereby identical reference characters designatecorresponding elements already described in their function andoperation. The upper insulator half shown in the right part of FIG. 2 isagain made up of a GFK half-pipe 20 and an insulator element 22 that ismanufactured from silicone and that comprises a part 22 that abutsimmediately on an outer surface of the half-pipe 20. The insulatorelement 22 also has two silicone shields 26 that extend at right anglesto said part 22 and are fashioned as semicircular disks. The position ofthe guide pins 28 on the cut surfaces of the silicone shields 26corresponds to the position of the bored guide holes 8 present in theinsulator element 4 of the other insulator half. The evacuation of airfrom the insulator body during the filling takes place via the boredholes 30 present in the half-pipe 20. Finally, the right part of FIG. 2shows the guide pins 10b arranged at a point inside the half-pipe 20corresponding to the position of the openings or sleeves 10 a.

FIG. 3 shows the lower insulator half with the GFK rod 14 fixed thereinby gluing, as well as one of the two GFK sleeves 32, each of which isslit. After the joining of the insulator halves, these sleeves 32 arepushed onto the respective cylindrical ends of the insulator, arerotated, and are glued to the GFK half-pipes 2 and 20.

FIG. 4 shows the ADL cable 16, arranged in the lower insulator half andoriented parallel to the GFK rod 14, with its sheath or cladding orjacket removed, to expose shortened aramide yarns or threads 34, as wellas a buffered cable 36.

During the assembly of the insulator, a twin-chamber sack containing forexample 2*50 g of a two-component silicone resin (preferably LSR -Liquid Silicone Rubber) is preferably used. After the mixing of the twocomponents, the silicone resin is applied to the opposed surfaces of theinsulator element 4 and 22, and shields 6 and 26, and the insulatorhalves 4 and 22 with the half-pipes 2 and 20 fixed therein are placedtogether and are heated to approximately 100° C. for approximately fiveminutes, and are thereby connected with one another in an adhesivefashion. Subsequently, the epoxy casting resin used as a fillingcompound, preferably Protolin 51, is brought, via the bored fillingholes 30, into the hollow body formed by the half-pipes 2 and 20 whichis sealed at its end by means of two silicone stoppers 18. The resinfuses with the ADL cable fixed in the half-pipe 2 by a plastic compound(e.g., Prestik), with the GFK rod 14 and with the half-pipes 2 and 20 toform a unit having tensile strength. During the filling with Protolin ofthe hollow space bounded by the two half-pipes 2 and 20 and the stoppers18, the insulator should be arranged horizontally.

FIG. 5 shows the insulator body, which is essentially of rotationallysymmetrical construction, during the filling. The epoxy casting resinused as a filling compound is brought into the hollow space by means ofa spray vessel 38, via a bored hole, whereby the air displaced by thecasting resin escapes via the bored hole 30.

We claim:
 1. An insulator for guiding an optical cable held on a phasecable of a high-voltage aerial line, said insulator being composed oftwo insulating parts, which are subsequently assembled around analready-assembled cable, each of the insulating parts comprising: asemi-circular half-pipe, the semi-circular half-pipe is stable both inthe transverse and longitudinal direction; and an insulator element, theinsulator element surrounds a portion of the half-pipe and is connectedto said half-pipe.
 2. An insulator according to claim 1, wherein each ofthe half-pipes is made of a glass-fiber-reinforced plastic and theinsulator element is made of silicone.
 3. An insulator according toclaim 2, wherein both the half-pipes and the insulator elements are eachprovided with corresponding guide pins and guide elements for assistingin assembling of the parts on an optical cable.
 4. An insulatoraccording to claim 3, wherein one of the half-pipes has a rod gluedtherein and protruding from the half-pipe, said rod being made of amaterial having a tensile strength.
 5. An insulator according to claim4, wherein the rod and the optical cable have approximately the samediameter.
 6. An insulator according to claim 3, wherein at least one ofthe half-pipes is provided with a filling hole to fill a cavity of theinsulator and a hole for evacuating of air.
 7. An insulator according toclaim 6, wherein the insulator includes a slotted sleeve being appliedto the ends of the half-pipes to facilitate connecting the half-pipestogether.
 8. An insulator according to claim 1, wherein both thehalf-pipes and the insulating elements are provided with correspondingguide pins and guide elements to facilitate assembling the half-pipes onan optical cable.
 9. An insulator according to claim 1, wherein one ofthe half-pipes has a rod glued therein, said rod protruding from saidhalf-pipe and being made of a material having a high tensile strength.10. An insulator according to claim 9, wherein the rod and the opticalcable have approximately the same diameter.
 11. An insulator accordingto claim 1, which includes a slotted sleeve for each end of thehalf-pipes, said sleeve being assembled on the assembled half-pipes tohold the half-pipes together.
 12. An insulator according to claim 1,wherein at least one of the half-pipes is provided with a filling holeto fill a cavity of the insulator and a hole for evacuating of air. 13.An insulator according to claim 12, which includes a slotted sleeve foreach end of the insulator, said slotted sleeve being assembled on theends of the assembled half-pipes to hold the half-pipes together.
 14. Aninsulator for guiding an optical cable held on a phase cable of ahigh-voltage aerial line, comprising: a first insulating part, the firstinsulating part comprising a first semi-circular half-pipe and a firstinsulator element, wherein the first insulator element is connected tothe first semi-circular half-pipe, and the first insulator elementsurrounds a portion of the first half-pipe; a second insulating part,the second insulating part comprising a second semi-circular half-pipeand a second insulator element, wherein the second insulator element isconnected to the second semi-circular half-pipe, and the secondinsulator element surrounds a portion of the second half-pipe; and atleast one slotted sleeve, the at least one slotted sleeve being attachedto an assembled end of the first and second half-pipe.
 15. The insulatoraccording to claim 14, wherein the first half-pipe is made of aglass-reinforced plastic and the first insulator element is made ofsilicone.